I am currently using Linux version 3.0.8 and it works just fine with the exception of some minor bugs. I watch the bug-tracker and see that some of the reported bugs are already fixed. Is there something like a nightly build that I can download and test?

The latest development snapshot 3.0.8 is the latest released version.I'm currently in the middle of a larger refactoring task related to splines (FS777) in preparation for QCAD 3.1. There will likely be more development snapshots before that.